Monday, January 3, 2011

Leafy Green Feedback

People these days are looking to conserve energy for a wide variety of reasons - financial, environmental, concern about dependence on foreign oil, generic anti-wastefulness, or (let's face it) just because it's what everyone else is doing. But it can be really hard for would-be conservers to make informed decisions on how to save if they don't know where their energy is being spent. That bill at the end of the month doesn't contain a whole lot of information, and that's a problem.

It all comes down to granularity, or the resolution of the information we receive about our use. A utility bill at the end of the month is very low-resolution, low-granularity - it's whole-home usage over the course of an entire month. We can't see which days we use more (weekends? weekdays?), which times we use more (probably evenings?), which appliances use more (TVs? Dryers? Refrigerators?). I dunno, do you?

Without this information, it's hard to know where to cut back, and psychology researchers have known this for a long time. Many studies have been conducted in which people are given more granular feedback on their energy use - daily, hourly, or even real-time - and oh, the savings, how they pile up. In a study by Petersen et al. at Oberlin college (2007), the authors set up an energy-saving competition among the dorms. All of the dorm residents had access to energy feedback (which was already an improvement for them, since dorm residents don't pay their energy bills, and so never see any information on energy use). Some of the residents were given their data on a weekly basis, while others could access their real-time energy use data online. The real shocker of this study, to me, was how much all of the dorms saved - even the low-resolution dorms showed a 31% drop in energy usage, particularly impressive because dorm residents have no control over their thermostats. But this saving shot up to an almost unbelievable 55% for the high-resolution dorms. These savings are on the high end, but in every study I'm aware of, the finding is the same: Feedback leads to conservation.

Clearly, there's a lot to this granularity thing. Can you imagine what it would be like if we could all see our own home's real-time energy use, or even better, see it at the level of an individual room or even appliance? When it comes to cleaning up our energy usage, the devil is in the details, and the better we can see him, the better we can exorcise him.

The most effective feedback systems should also make the information relevant to the user. Not all of us know what a kWh (kilowatt hour) is, or what it means to be using 50 of them instead of 40 of them. But if this feedback were in the form of dollars out of our pockets, or CO2 being released into the atmosphere, or money into the hands of foreign nations, we would probably be a little more personally motivated to do something to reduce it.

Enter the smart meter. All over the nation, utilities are replacing regular energy meters with "smart meters", which allow better communication between the home and utility, and provide information every hour (or even every 15 minutes, for some). If you have one, it's likely your utility's website will allow you to go online and see your energy use broken down by day or even more finely, rather than by month.

This is an embarrassing admission for someone who studies energy efficiency, but I just found out that the townhouse I've been renting for two years has a smart meter. It was upgraded at some point and I never knew, and it's opened a world of information. See, here in Arizona, energy bills notoriously double or triple during the summer because A/C use shoots up. But I just went online and saw that on days where the temperature goes up, my energy use goes down, which makes absolutely no sense...of course, it would be great to have more granular information and see if the energy use has anything to do with A/C, but I can't tell that based on the information given. On the other hand, I've learned that my roommates and I need to be much more careful to consider time of use, because on some days almost half of our energy use has been during on-peak hours. Yipes.

To find higher-resolution information about your own home's energy use, check and see if your home has a smart meter (you can either call the utility or check your monthly statement). If you don't have one, you can ask if and when they plan on installing them in your neighborhood, because chances are they may be soon. And if still not, you can look into purchasing a TED or a Kill-A-Watt to show even finer granularity.

I forget who, but someone suggested that an energy bill should look like a phone bill - device, times, amounts, cost. I couldn't agree more. If it did, no matter our personal motivation, we would all be much more able to make informed decisions to curb our energy use.